Soaring fuel costs, peaking fuel production and dwindling reserves, conservation efforts, and environmental concerns have increased public awareness of the fuel efficiency issues posed by automobiles and other vehicles. Internal combustion engines are often inefficient in combusting fuel in that they fail to completely burn all of the fuel entering a combustion chamber of the engine. This unburned fuel can remain within the combustion chamber where it forms unburned hydrocarbon residues that accumulate on an interior wall of the combustion chamber as well as other surfaces that play a role in the combustion process. These residues are problematic because, when incinerated, they are discharged as toxic and harmful exhaust emissions such as soot. These unburned hydrocarbons may also react with nitrogen oxides, which are also produced during fuel combustion, upon exposure to ultraviolet light to form ozone. The unburned hydrocarbon residues interfere with fuel combustion and reduce the power output of the engine. Additionally, with the present low levels of sulfur in fuels, the internal combustion engine and its parts such as the exhaust valve experience additional friction that was reduced by the lubricating effects of the sulfur previously found in most hydrocarbon fuels.
Conventional fuel additives may also be disadvantageous due to the necessity of including a carrier or substrate that may permit the active ingredients of those products to attach to the interior surface of the combustion chamber of the internal combustion engine. Carriers and substrates in these conventional fuel additives may include toxic compounds that increase production costs and harm the environment when emitted in vehicle exhaust emissions. The failure of many conventional fuel additives to coat the combustion chamber's interior surface to prevent the formation and accumulation of residues thereon decreases the efficiency of the engine in combusting fuel. Less fuel is combusted by the engine and more fuel is wasted as combustion by-product residues that are deposited onto the interior surface of the combustion chamber.
Another disadvantage of conventional fuel additives is that many include precious metals such as platinum to act as catalysts. The use of catalytically-active precious metals is undesirable due to the high costs of production of such fuel additives.
An additional disadvantage of conventional fuel additives is that many are water soluble and cannot be dissolved in oil. The insolubility of many conventional fuel additives in oil reduces the effectiveness of the fuel additives in improving fuel efficiency. Oil-insoluble conventional fuel additives must be mixed with an oil-soluble compound prior to use, thereby increasing the cost of production. Conventional fuel additives may also include other environmentally-harmful compounds, such as naphthalene, which may be toxic to animals, plants, humans, and other organisms.
Another disadvantage of many conventional fuel additives is their failure to reduce the emissions of volatile organic compounds (VOCs) and nitrogen oxides in vehicle exhaust, which are produced as byproducts of fuel combustion. Both VOCs and nitrogen oxides undergo a chemical reaction in the lower atmosphere upon exposure to ultraviolet light to form ozone, which is a hazardous smog-forming pollutant that has been linked to respiratory illnesses and lung tissue damage in humans.
Conventional fuel additives have not included a source of boron because many boron-containing compounds create a thin layer of boron oxide that deposits on the combustion surfaces of an internal combustion engine. This thin layer of boron oxide produces longer ignition delays, and thus, reduces combustion efficiency.
Conventional fuel additives have also not included a source of cerium because most conventional fuel additives work as detergents or solvents to physically affect fuel in an effort to increase the efficiency of combustion. In addition, many cerium-containing compounds have proven difficult or disadvantageous for usage in fuel additives, and thus, have been avoided by the makers of conventional fuel additives, due to the undesirable byproducts precipitated from ceric salts and cerous salts used to produce cerium metal. Ceric salts that are undesirable for producing cerium metal to be used in fuel additives include ceric fluoride, ceric oxide, and ceric sulfate. Cerous salts that are undesirable for producing cerium metal to be used in fuel additives include cerous bromide, cerous carbonate, cerous chloride, cerous fluoride, cerous iodide, cerous nitrate, cerous oxalate, and cerous sulfate. These ceric and cerous salts are not solvent-soluble and do not yield cerium metal with a high level of purity. Cerium metal derived from these ceric and cerous salts is not oil-soluble and must be finely ground into nanoparticles and complexed with a fuel-soluble compound before introduction into an internal combustion engine. The production of nanoparticles of cerium metal would greatly increase the costs of producing cerium-containing fuel additives using conventional technologies.